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4 years ago

in a history class, the girl to boy ratio is 9 to 5. if there is a total of 70 students how many boys is there

Mathematics

2 answers:

DedPeter [7]4 years ago

7 0

Answer:

25 boys.

Step-by-step explanation:

To solve this problem, first add the two parts of the ratio. 9 + 5 = 14. Then divide 70 by 14 to get 5. Since the total is 5 times the ratio total, multiply both sides of the ratio by 5. The result is 45 : 25. If you add them together, you get a total of 70. Therefore, there are 25 boys in the class.

RUDIKE [14]4 years ago

3 0

Answer:

There are 25 boys in the class.

Step-by-step explanation:

9-5

9-5=18-10

9-5=27-15

9-5=36-20

9-5=45-25

45+25=70

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3 years ago

This is Matrix for pre calc

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The given system of equations in augmented matrix form is

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If you need to solve this, first get the matrix in RREF:

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Add 11(row 2) to -5(row 3), and 19(row 1) to -5(row 4):

$\left[\begin{array}{cccc|c}3&2&-4&2&-23\\0&5&-6&8&-58\\0&0&-91&153&-823\\0&0&-164&132&-1052\end{array}\right]$

Add 164(row 3) to -91(row 4):

$\left[\begin{array}{cccc|c}3&2&-4&2&-23\\0&5&-6&8&-58\\0&0&-91&153&-823\\0&0&0&13080&-39240\end{array}\right]$

Multiply row 4 by 1/13080:

$\left[\begin{array}{cccc|c}3&2&-4&2&-23\\0&5&-6&8&-58\\0&0&-91&153&-823\\0&0&0&1&-3\end{array}\right]$

Add -153(row 4) to row 3:

$\left[\begin{array}{cccc|c}3&2&-4&2&-23\\0&5&-6&8&-58\\0&0&-91&0&-364\\0&0&0&1&-3\end{array}\right]$

Multiply row 3 by -1/91:

$\left[\begin{array}{cccc|c}3&2&-4&2&-23\\0&5&-6&8&-58\\0&0&1&0&4\\0&0&0&1&-3\end{array}\right]$

Add 6(row 3) and -8(row 4) to row 2:

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4 years ago

Factor out the GCF -2x^2 - 4x - 6

andrew-mc [135]

The Greatest Common factor(GCF) of -2x^2-4x-6 is -2(x+1)(x-3)

<h3>What is Greatest Common Factor?</h3>

The greatest common factor (GCF) is the largest factor two or more numbers have in common

From the question,

-2x^2-4x-6

By collecting like terms

-2(x^2-2x-3)

By factoring x^2-2x-3

-2(x^2-3x+1x-3)

Collecting like terms

-2(x^2-3x)+(x-3)

-2(x(x-3)+1(x-3))

-2(x+1)(x-3)

hence -2(x+1)(x-3) is the Greatest Common factor of -2x^2-4x-6 is

Learn more about Greatest Common factor on:brainly.com/question/219464

#SPJ1

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zhannawk [14.2K]

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